1. Field of the Invention
This invention relates to an apparatus for inspecting semiconductor wafers.
2. Description of the Prior Art
In the process of producing integrated circuits, it is important to inspect wafers for improvement of the yield of the production. In particular, such inspection is extremely important in the photolithographic developing process, which coats photoresist on a wafer and forms a masked pattern on the wafer.
In the past, wafers have been manually inspected by special inspectors with their own eyes to judge the effectiveness of the production process. This inspection was broken down into whole wafer inspection using oblique light irradiation, i.e., macroscopic inspection, and inspection of certain points on a wafer surface using a microscope, i.e., microscopic inspection.
More recently, an inspecting apparatus having a carrying section has become available. This equipment stores the coordinates of pre-determined inspection points and permits whole wafer visual inspection and microscopic visual points inspection using a microscope without the need for manual contact with the wafer.
Even with this recent apparatus, however, macroscopic whole inspection and microscopic point inspection must be performed manually by special inspectors with their eyes for judgment. This requires training of special inspectors. Further, variations of inspection result from such factors as the health or subjective views of different inspectors.